Oxidation process.



purification, except air and care should 1 STATES PATENT OFFICE.

OARLETONELLIS, OF MONTCLAIR, NEW JERSEY, ASSIGNO R OF TWO-THIRDS T0ELLIS- EOSTER COMPANY, A CORPORATION OF NEW JERSEY, AND ONE-THIRD TOCHARLES In. PARSONS,

OF WASHINGTON, DISTRICT OF COLUMBIA.

OXIDATION PROCESS.

11,103,017. No Drawing.

Processes, of which the following is a specification.

This invention relates to a process of making sulfuric acid or sulfuricanhydrid by contact-of sulfurous acid with a catalyzer preferablycarrying selenium or tellurium or similar non-metallic element orcompounds thereof.

In the manufacture of sulfuric acid platinum has been used extensivelyas a contact material and has shown great susceptibility to the actionof certain bodies denoted as catalyzer poisons, including arsenic and soforth, so that the purification of the gases which are to pass throughthe catalyzer material has to be carried out with great care and at ahigh-cost. It has also been proposed to use oxid of iron as a catalyticmaterial, but in this case the conversion is very poor so that a largeamount of sulfurous acid passes through the catalyzer unchanged and hasto be treated finally by the aid of the active platinum bodies.

In the present invention it is one object among others to provide aprocess which does not call for the same complete or extremepurification of the gases" or in which for the purpose of removin dust,maybe eliminated entirely. For this purpose, I employ in the process ofthe present invention a catalyzer of the type of tellurium or certain ofits compounds, or other similar allied'bodies. Seleniummay be likewiseemployed, but the tellurium is preferable owing to higher volatilizationpoint. Tellurium compounds are in some cases volatile in a current ofhighly heated therefore be taken to maintain the temperatures. undersuch circumstances, below the volatilization or, subliming point of thecatalytic material. Besides the element tellurium and selemum, one mayuse, as stated, other compounds thereof, such as selenium'dioxid,selenious acid, selenic acid and other compounds of selenium. Alsotellurium monoxid and diom'd, tellurous acid, tellurium trioxid andtelluric acid, and the salts of these acids Specification of LettersPatent.

the temperature required Patented Jul 7, 1914.

Application filed September 16, 1912. Serial No. 720,497.

such as selenites and selenates; tellurates and tellurites of thealkalis and alkaline earths and of the higher metals.

In order to secure a suitable surface of contact, I preferablydistribute material over a support such as fragments of pumice, asbestosfiber, fullers earth, charcoal and the like. Or, I may use water solublesalts as a temporary supporting basis and wash out the salt afterformationof the catalytic material, so as to roduce a skeleton of thecatalytic body. 8r a water soluble salt may be used as a supportingmaterial throughout the operation.

As an example of the operation of catalytic material asbestos fibers areimpregnated with a solution of tellurium or telluric acid and thentreated with sulfur dioxid to precipitate the tellurium coatingz'n thenbe purified and site. This mass may formed into a deep bed which may beheated by externally applied heating means up to for starting thecatalytic operation. Through the catalytic bed is passed a mixture ofair or oxygen, steam or water, vapor of sulfurous acid or equivalentbodies. The catalyzer acts to carry oxygen to the sulfurous acid andwith the moisture present sulfuric acid is formed. It is sometimesdesirable to have an excess of moisture present, because of itsfavorable action to the oxygen, but under certain circumstances theproportion of water maybe considerably reduced or even entirely omitted.The air or oxygen supply preferably also should be in excess, thisbeing, however, variable with respect to other conditions. In order toavoid clogging of the catalyzer bed it dust carried by the gases derivedfrom pyrites burners or other sources. The removal of bodies poisonousto platinum is not usually necessary or desirable. ing the gasesessentially to remove the dust in general suffices to put the gas incondition for passage through the catalyzer bed. The temperatureemployed should be below that of the volatilizing point of thecatalyzer, and of course, should be kept below the point at whichsulfuric andhydrid dissociates to any objectionable degree. It may evenbecome necessary to cool the porous catalyzer bed after the process iswell under way in order to prevent these Washis desirable to remove the1 ios . ing tellurium containing prising with a catalyzer of a highlysensitive nature.

The vigor of tellurium compounds is gen-' by the presence of a smallamount of an activating material. Seleniumand other similar bodies servefor this purpose, 5 to 15% usually being sufficient. The catalyticmaterial prepared by dissolvtraces of selenium in diluted nitric acid, ading asbestos fibers to absorb the solution, drying and gently ignitingmay also be employed. If the nitric acid solution withoutthe asbestosfiber is concentrated a precipitate of tellurium dioxid forms which maybe made the basis of a catalytic material. The amount of moisture whichunder some circumstances may be present during the contact of sulfur diverally enhanced oxid with the catalyzer may be that which.

suffices merely to form sulfuric acid or the proportion may be larger,so that somewhat diluted acid forms.

No drawings are shown in the present application as the process is clearfrom the foregoing without graphic delineation.

What I claim is 1. The process of oxidizin' sulfur dioxid and formingsulfuric acid w ich comprises bringing a mixture comprising sulfurdioxid and oxygen into contact with essentially a non-acid, non-metalliccatalytic body consisting substantially of metalloidal bodies; saidcatalytic body being substantially unaffected in its catalytic action inthe conversion of sulfur dioxid into sulfur trioxid in the presence ofsmall quantities of bodies toxic to metallic catalyzers.

2. In the process of making sulfuric acid, the step of oxidizing sulfurdioxid which comprises contacting moist sulfur dioxid with telluriumcontaining material in the presence of regulated quantities of oxygen.

3. The process of-making sulfuric acid which comprises bringing amixture comprising sulfur dioxid, oxygen and water vapor into contactwith a tellurium containing catalyzer carrying traces of a seleniumactivator.

4. The which comprises bringing a mixture comsulfur dioxid, oxygen andwater vapor, all in an unpurified condition but free from dust, intocontact with a catalyzer of tellurium containing material carryingtraces of a selenium activator.

- 5. The process of making sulfuric acid which comprises bringing amixture comprising sulfur dioxid, oxygen and Water vamay be employed,especially process of making sulfuric 'acid' por, all in an unpurifiedcondition but free from dust, into lurium containin catalyzer carryingtraces of a selenium act1va-tor.

6. The process. of making sulfuric acid which comprises bringing amixture comprising sulfur dioxid, oxygen and water vapor, all in anunpurified condition but substantially free from dust, under pressureinto contact with a heated tellurium containing catalyzer carryingtraces of a-selenium activator.

7. The process of .making sulfuric acid which comprises bringing amixture comprising sulfur dioxid, oxygen and water, vapor, all in anunpurified condition but substantially free from dust, underpre'ssureinto contact with a catalyzer comprising tellurium and seleniummaterial.

J 8. The process of making sulfuric acid which comprises bringing amixture comprising sulfur dioxid, oxygen and water vapor into contactwith an oxid of tellurium. 9. In the process of making sulfuric acid thestep of oxidizing sulfur dioxid which comprises bringing a mixturecomprising sulfur dioxid and oxygen into contactwith a porous bed ofc'atalyzer comprising tellurium dioxid. 10. In the process; of making asulfuric acid, the step. .of'-"oxidizing sulfur dioxid which comprisespassing a mixture compriscontact with a heated teling air and sulfurdioxid through a porous bed containing catalytic tellurium containingmaterial maintained at a temperature substantially above atmospheric butbelow the volatilizing point of said material.

11. In the process of making a sulfuric acid, the step of oxidizingsulfur dioxid which comprises passing a mixture comprising air andsulfur dioxid under pressure through a deep bed of heated telluriumcontaining material supported on an inert carr1er.

12. In the process of making sulfuric acid, the step of oxidizing sulfur'dioxid which comprises mixing with an oxygen carrying gas andcontacting the mixture with tellurium containing material.

13. In the process of making sulfuric acid, the step of oxidizing sulfurdiox1d wh1ch comprises contacting sulfur dioxid 1n the presence ofoxygen with mixed tellurium and selenium material.

Signed at Montclair Essex and State of New Jersey this 13th day ofSeptember A. D. 1912.

GARLETON *ELLIS':

Witnesses:

B. M. ELLIS, F. OARBUTT.

in the county of:

